Calendered weft inserted wrap knit fabric

ABSTRACT

A 2-warp knit, weft inserted fabric having the face thereof calendered to produce a fabric when a PVC film is laminated thereto that has a surface roughness of 2.0 microns or below.

[0001] This invention relates generally to a coated or laminated fabricwhich can be printed evenly and clearly on both sides and in particularto a calendered weft inserted warp knit fabric for such use in laminatedor coated fabrics or applications.

[0002] Prior to this invention, weft inserted, warp knit fabrics weresupplied to the customer generally in the condition that it comes offthe knitting machine and the customer usually applied any furthertreatment required by them for their particular use. Warp knit faricswith weft inserted yarns therein generally provided a face side whichwas rough and uneven due to the weft inserted yarns which did not allowgood adhesion for a film or other substance to be laminated or coatedthereon.

[0003] Therefore the object of the invention is to provide a warp knit,weft inserted fabric which when coated or laminated provides excellentadhesion as well as printability.

[0004] Other objects and advantages of the invention will become readilyapparent as the specification proceeds to describe the invention indetail with reference to the accompanying drawings in which:

[0005]FIG. 1 is a schematic representation of the process of treatingthe warp knit, weft inserted fabric;

[0006]FIG. 2 is a schematic representation of the process to laminatethe fabric treated in FIG. 1;

[0007]FIG. 3 is a cross-section of the fabric produced by the treatmentsshown in FIGS. 1 and 2;

[0008]FIGS. 4 and 5 are schematic representations of the equipment usedto measure surface roughness of a fabric;

[0009]FIG. 6 is a table comparing surface roughness of an untreated anda treated warp knit, weft inserted fabric; and

[0010]FIGS. 7 and 8 represent, respectively, a running graph of themeasurements made by the equipment of FIGS. 4 and 5 on the untreated andtreated fabric.

[0011] Looking now to the drawings and especially to FIG. 1, a roll ofwarp knit, weft inserted fabric 10 is shown being processed and taken-upon the surface driven roll 12. The preferred warp knit, weft insertedfabric is a two bar, 100% polyester fabric having a 70 deniermultifilament stitch yarn, a 1000 denier multifilament warp yarn and a1000 denier multifilament weft inserted yarn.

[0012] The fabric 14 from the supply roll 10 is supplied over a seriesof guide rolls 16, 18, 20 and 22 to the calendering machine 24 whereinthe face of the fabric 14 is calendered between the heated steel roll 26and the rubber coated roll 28 wherein the weft inserted yarn 74 iscrushed to provide a smooth face. From the calendering machine 24 thecalendered fabric 15 is guided by the rubber roll 32 to the inspectionmachine 34 and then, after inspection, is guided by another series ofrolls 36, 38, 40 and 42 to the take-up roll 12 driven by the surfacedrive rolls 44 and 46.

[0013] In the preferred form of the invention the face calendered fabric15 is taken-up on the take-up roll 12 and delivered to the machine shownin FIG. 2 but obviously, if desired, the face calendered fabric 15 couldbe delivered continuously in line with machine in FIG. 2. From the roll12 the face calendered fabric 15 is guided into the nip of heated steelrolls 48 and 50 by a series of idler rolls 52, 54 and 56 wherein it ismated with a PVC thermoplastic film 58 from rolls 60 to provide thecoated fabric 62 shown in FIG. 3. From the nip of calender rolls 48 and50, the coated fabric 62 is taken upon a take-up roll 64 driven bysurface drive rolls 66 and 68.

[0014] The fabric 62, as shown in FIG. 3, consists of the outer PVC filmlayers 58 and the calendered warp knit, weft inserted fabric 15consisting of warp yarns 70, stitch yarns 72 and weft inserted yarns 74.The fabric 62, in the preferred form of the invention is 19-20 milsthick with each of the films 58 being approximately 5 mils thick. Thisparticular fabric is desirably used as a banner fabric which can beprinted on both sides due to the evenness or smoothness of the face ofthe warp knit, weft inserted fabric.

[0015] To measure the surface roughness of the face of the calenderedwarp knit, weft inserted fabric after it has been laminated to the film,the surface tester machine 76 shown in FIGS. 4 and 5 is used to obtainthe data shown in FIG. 6 and the graphs of FIGS. 7 and 8. The surfaceroughness tester machine illustrated is a KES-FB-4 machine sold byKato-Tekko Co., Ltd. of Kyoto, Japan.

[0016] The sample 78 of the fabric 62 to be tested is clamped at one endto the winding drum 80 by chuck 82 and to the chuck 84 at the other end.A transducer (not shown) is hooked to the cage 86 to record the up anddown movement thereof as dictated by the finger 88 as it senses the faceof the fabric sample 78 as it moves back and forth thereunder byrotation of the winding drum.

[0017] Looking at FIG. 6 the mean deviation in microns of the warp knit,weft inserted fabric before and after calendered as shown in FIG. 1 andtreated as in FIG. 2 is shown with the face of the calendered fabric Ahaving a surface roughness of less than 2.0 microns whereas the face ofthe sample fabric coated without calendering had a surface roughnessalmost four times greater. Note the difference in amplitude of the faceof the non-calendered fabric in FIG. 7 versus that of the calenderedfabric in FIG. 8. It is clearly evident that the fabric of FIG. 8 isvery smooth which increases the adhesion of the warp knit fabric to thefilm as well as enhancing the printability on the surface thereof.

[0018] It is abundantly clear that the calendered warp knit, weftinserted fabric has a face with a surface roughness of less than 2.0microns which can readily be used as a banner fabric on which the facecould be printed or in other applications such as a substrate forroofing fabric where adhesion and thickness is a factor or in a tentingfabric where smoothness thereof makes it more readily cleanable. Asindicated the use of the warp knit, weft inserted fabric for theproduction of banner material is the preferred use thereof but othersuitable uses may be made thereof where a low surface roughness below2.0 microns is necessary to provide a viable product.

[0019] The above described embodiment is given for the purpose ofillustration only and it is understood that improvements andmodifications may be made without departing from the scope of theinvention as defined in the claims set forth below.

We claim:
 1. A warp knit, weft inserted fabric comprising: warp yarnsand weft inserted yarns connected thereto with stitch yarns and havingthe face thereof calendered to provide a surface roughness of less than2.0 microns when the face thereof is covered with a thermoplastic film.2. The fabric of claim 1 wherein all of said yarns are polyester.
 3. Acoated fabric having a substrate and a film connected to face and backside thereof, said substrate having a warp knit, weft knit fabric withthe face thereof calendered thereof to provide a surface roughness ofless than 2.0 microns.
 4. The coated fabric of claim 3 wherein the backside thereof is calendered.
 5. The substrate fabric of claim 4 whereinsaid fabric is combined of 100% polyester yarns.